The invention relates to an apparatus for producing a collimating mark within an optical sighting device.
German Offenlegungsschrift 33 19 392, published on Nov. 29, 1984, discloses an optical sight for barreled weapons which has a collimating mark visible therein for lead and/or elevation marking. The mark is generated using light-emitting diodes and is optically superimposed in the sighting ray path. A stable and temperature-insensitive display is controlled directly by a computer. The brightness of the display is controlled so that the optical sight is suitable for both daytime and nighttime operations. For controlling the brightness of the display a light guide is coupled to each of the light-emitting diodes. The light-emitting diodes are arranged in a matrix manner in rows and columns. The diameter of the light guide is, at least at the point where light emerges, substantially less than the dimensions of the light-emitting diodes. The faces where light emerges are arranged next to one another and are connected to reflecting optics for combined reflecting into the sighting ray path. To obtain high resolution, a large number of light sources and light guides is necessary. The requirement for a large number of light sources and light guides makes assembly difficult and expensive.
United Kingdom Patent Publication GB-A 2119 125, published on Nov. 9, 1983, discloses an optical sighting device which has a lens, two prism arrangements, and an eyepiece as well as a collimating mark. The collimating mark is superimposed on the image to be observed and usually lies in the center of the image field. In this conventional apparatus, a mean value of the brightness of the overall target area is derived. The brightness of the collimating mark is compared with the mean value to control the brightness of the collimating mark. This control technique does not take into consideration the immediate surroundings of the collimating mark, that is, the contrast between the collimating mark and the background. Furthermore, control of the collimating mark with respect to the display of the ballistic aiming point is not performed.